The association's chairman, Alfred Obranic on Friday described Nazism and communism as the worst evils in the history of humankind.
Obranic said that in the wake of the Second World War, 100,000 Croats were killed without trial, and an additional 100,000 were sent to prisons and labour camps.
His deputy, Jure Knezovic, said that while other nations paid tribute to their victims of the communist system, Croats were "ruthless" towards victims among their own people.
He criticised the national parliament for rejecting a proposal to establish a museum or an institution to research communist crimes.
The draft resolution, which the Parliamentary Assembly will discuss next week, provides for "measures to dismantle the heritage of the former communist totalitarian systems".
"The totalitarian communist regimes which ruled in Central and Eastern Europe in the last century, and which are still in power in several countries in the world, have been, without exception, characterised by massive violations of human rights," the document says.